Currently, at least as measured by the Program for Student International Assessment (PISA), America's students from each level of family income perform more poorly than students in the most educationally successful countries. Ripley thus sets out to draw lessons from Finland, South Korea, and Poland, which have achieved strong educational gains for their students. Certainly, as we digest—year after year—data on our own students that attests to their middling performance on international comparisons, tragic and persistent learning gaps among different segments of the population, and depressingly high college remediation rates, lessons from the best-performing countries in the world could not be more welcome.

What is thus surprising about Ripley's book is how little it contains that is really news; instead, it serves to remind us in powerful terms that we simply haven't acted on what we already know. Education systems work when

Students are challenged with demanding and coherent curricula;

Teachers are recruited from the top echelon of college graduates;

We tell the truth to students about their performance; and

Teachers, students, and parents are all committed to the difficult work of constant educational progress.

I over-simplify, but not by much. Ripley offers some notable insights: Poland made great progress by delaying tracking, high-performing countries often spend the most on their poorest students, and parental involvement in schools counts for far less than what they do with their children at home. But in the end, the book hammers home a single message: Where schools exist "to help students master complex academic material"—and only that—students succeed.

To put the matter bluntly, if all U.S. schools applied the rigor and attention to their academic offerings that our high schools pay to their highest-profile sports programs, our students would come far closer to matching their demographic peers in high performing countries. (In one of her many arresting paragraphs, Ripley describes the physical-education standards American students must meet to pass the Presidential Fitness Test. That test—alone among all our assessments—is in fact the most rigorous in the world).

The lesson for those who would reform American education is clear. We are right to work for higher standards and better teacher preparation; it's smart to realize that grit and self-discipline and determination matter alongside grades and test scores. But in the end, we simply have to do what we seem to find most difficult: teach demanding material well and not constantly underestimate our students' capacity to rise to the challenge. This means creating a teaching profession that draws in our best, and asking those teachers to teach a rigorous curriculum that progressively habituate our students to serious thinking, mastery of complex skills, and sustained study-habits. Ultimately, this is what it will take to build an effective progression from pre-K to college and/or careers.

We are taking, certainly, small steps: the Common Core State Standards invite a more rigorous curricula across the country. But such standards neither create such curricula nor do they assure assessments that will provide high-quality information on how our students are progressing in meeting the standards. Issues of cost and design suggest that optimism on this front is premature.

We have modestly upgraded the demands on our schools of education, which will now, in order to be accredited, have to have some publicly accountable academic admissions criteria and will eventually be held accountable for the teaching effectiveness of their graduates. But until we close the many, many weak programs whose graduates simply haven't been prepared to teach effectively (as Finland did, and Norway, with the inevitable consequences, did not), we will not make a serious impact on new teacher quality. Nor will we be able to fill the more rigorous teacher preparation programs with outstanding applicants until we re-think the teaching conditions and career structures in our public schools.

We have begun to tell something of the truth to students and parents alike in a few states that, like New York, have radically raised their standards for academic proficiency—but we have yet to tell such truths to high-school students, restricting our work to date to earlier grades where the stakes are lower.

Why has doing the obvious on behalf of our students proved so difficult?

Our heterogeneous culture and cult of localism have made it extremely difficult to agree on a rigorous, shared conception of academic content in English Language Arts (ELA) and social studies—and even science. As a country, we have avoided sustained consideration of what an educated American should know and be able to do. A merited guilt about deep and persistent economic inequality has too often translated into patronizing condescension about the capacity of disadvantaged students to hear the truth about their performance and then to raise it—dramatically—if they are taught effectively. Our post-World War II economic boom gave too many parents the sense that reasonable success was almost inevitable regardless of their children's educational achievement, which in turn left us—collectively—relatively indifferent to the caliber of our teachers. And our history of locally funding so much of our public school expenditure has undermined most serious efforts to remedy the per-student funding gap between affluent and poor districts.

In the end, if we are serious about preparing a far higher percentage of our students for college-readiness, we have to get serious about being serious. This means, above all, telling the truth: the truth about how little, academically speaking, we demand of our students, how poorly we select and prepare their teachers, how ineffectively we fund education, and how little effort too many of us make to work with our children to ensure that they come to see sustained hard work as the vital path to a better future. I leave the last words to Ripley. Writing of the experience of Finland's students, Ripley comments:

I started to suspect that the answer was fairly straightforward. They took school [in Finland] more seriously because it was more serious. And it was more serious because everyone agreed that it should be.

David M. Steiner is the founding dirctor of the CUNY Institute for Education Policy at the Roosevelt House and the Klara and Larry Silverstein Dean at the Hunter College School of Education. Steiner served as New York State's commissioner of education from 2009 to 2011.